When it comes to avalanches knowledge is paramount. The best way to not become an avalanche victim is not to get caught in one; AVALANCHE AVOIDANCE is the first rule in avalanche terrain.
Of course, when you see an open field of untouched powder, it is very hard to resist flying straight down, especially as the race for first tracks get ever more competitive with more and more people skiing off-piste. But there are a number of things you should think about and be aware of every time you venture beyond the marked pistes.
Off-piste skiers should have the knowledge and experience to read and predict all the variables such as the weather, terrain and snowpack. If you don't have this knowledge you should go with someone who does, preferably a mountain guide. Selecting when a slope is safe is vital; just following someone else's tracks does not make it safe!
The best place to start is with the local avalanche bulletin. Each day they will give a rating of 1 to 5 on the avalanche risk (with 5 being the highest). The avalanche report will also contain more specific and detailed information such as which slopes are most prone, where wind slabs may have formed etc. If you are still unsure, consult a pisteur in the resort - they have invaluable local knowledge.
The weather is crucial in avalanche prediction. When and how much it last snowed, as well as wind speed and direction are crucial factors. You should know, and know how to interpret, this information. The first 24 hours after a heavy snowfall are the most dangerous time for avalanches. This danger is greater still if the snowfall has been accompanied by strong winds.
Many factors go into determining the stability of the snow pack. If you find yourself on a slope and are still unsure of its safety you can dig a snow pit and analyse the different layers of snow to establish the risk of sliding. You will quickly be able to see if there is underlying weak, poorly-bonded snow. The reality is, however, that the majority of people who go off-piste have neither the knowledge nor the inclination to do this.
The terrain is a crucial factor. There are a number of questions to ask when assessing a slope's safety:
Is the slope historically prone to avalanche? There are natural avalanche chutes which are obvious to see. Other slopes may be particularly prone to wind loading due to their orientation. The nature of the terrain under the snow pack is important - smooth, grassy slopes are much worse at holding snow while rocks and trees can both help anchor it.
Have there been a lot of avalanches this winter? The number of avalanche incidents there has been that winter can give an indication of the general stability of the snow pack. How the snow pack builds up over the course of a season can have an important impact. When the snowfalls have occurred, the temperature changes there have been, and the behaviour of the wind all go to determining the nature of the snowpack.
How steep is the slope? Slopes over 30 degrees are the most avalanche prone. Those under 25 degrees are much less dangerous - but also less fun to ski! The most dangerous slopes are those between 35 and 45 degrees. Steeper than this, the danger reduces again as snow tends to slough of regularly rather than form slabs.
Are you threatened by other dangers from above? While the majority of avalanches are triggered by a person, there are a few other dangers to be aware of. You should always take note of what is above you. Are you skiing under a dangerous slope? Also beware of cornices and seracs collapsing above you. These are hard to predict so the best advice is to spend as little time as possible underneath them.
Is it convex or concave? Convex slopes are more prone to avalanche, though don't assume that concave slopes are always safe.
On what aspect is the slope? This determines how much sun and wind the slope receives, both crucial factors in determining avalanche danger. In the Northern hemisphere northerly facing slopes tend to have more avalanches in mid-winter, while in the spring the southerly slopes are more prone
How much sun has the slope received? A slope that has received a lot of sun is more prone to sliding; this is why it is always safer to descend most slopes in the morning. This is especially important in the spring
Is the slope wind affected? The amount of wind and the direction that it has blown is crucial. If the wind has arrived from behind the slope it may very well be wind-loaded making it susceptible to wind slab avalanches which are often very large. If the wind has come up the slope it will be much safer, but then the snow quality won't be as good.
What is the exposure and run-out like? If you are skiing above cliffs or near crevasses for example an avalanche can quite easily be deadly without having to bury you. If there is a small avalanche path with few obstacles and gentle run out you are more likely to be able escape in tact.
It is a very hard thing for any off-piste rider to back away from a perfect powder slope, but if your knowledge and your instinct are telling you no then you must.
If you decide that the slope is safe enough there are a few simple rules you can follow to make the descent safer.
Firstly you should never ski alone off-piste; there is no-one to help you in case of accident. A group of three or four is ideal, a group above six becomes too large logistically and can pose it own dangers.
You should ski the slope one by one so as not to load the slope more than is necessary. Also if you all get avalanched together it leaves no one to perform a rescue. The others in the group should watch the skier in case anything happens.
The party should plan where to re-group and this should be a safe waiting place, eg behind some rocks, where you will not be caught in the slide if the slope avalanches. Do not ski directly above your partners. Try to avoid traversing dangerous slopes. If you must, keep a good distance between you and do not traverse above others.
There are many things to consider with avalanches. Arming yourself with the knowledge is crucial. Experience is important too, and the more time you spend in the mountains the better you will become at recognising the dangers. Luck also plays it part, since no matter your knowledge and experience, the mountains remain an unpredictable place. You shouldn't be afraid to ski off-piste; it is an extremely rewarding sport when practised safely. The best thing you can do is to gain as much knowledge and experience as you can, have the right equipment, and always respect the dangers of being in the mountains.
It is essential that you travel with avalanche safety equipment at all times and know how to use it.
Statistics show that after 15 minutes of burial, survival chances drop dramatically. This means that your best chance of being pulled out of an avalanche alive lie with you being rescued by your ski partners. By the time rescue services arrive on the scene it is almost always too late.
The three essential items you need are transceiver, shovel and probe. Everyone in your party should carry these three items at all times. It is no good having one shovel between you if that person is the one buried.
There are a number of different types of transceiver available. More information can be found on our transceiver page. Generally the digital models, such as the Tracker DTS, are the easiest to use and good for those that don't spend a lot of time practising.
The probe is used for locating the exact position of the victim after your transceiver has led you there. This ensures you begin your dig in exactly the right place. A good shovel is essential as the snow can often set very hard after an avalanche and you may have to remove a large amount before you get to the victim. Having the right shovelling technique is equally important.
The Avalung is another useful piece of equipment. It allows you to breathe even when you are buried deep in the snow. It is in effect an artificial air pocket and can greatly increase the time you can survive under the snow.
If you do get caught in an avalanche there are a number of things you can do to help your chances, although the size and power of the avalanche will determine the ease or not of these tasks.
You should, if possible, try to ditch your backpack and poles, as their extra weight can drag you down.
You should always try to stay on the surface of the avalanche. The best way to do this is to use a swimming motion.
If you are near the surface when the avalanche is stopping try to thrust a part of your body to the surface to give the searchers a visual clue.
If you are buried you should try to create yourself an air pocket before the snow sets. The best way is to use your fists in a punching motion around your face. The snow can set extremely hard after an avalanche so this will be a crucial help to your survival.
This is the most dangerous type off avalanche to an off-piste skier. Slab avalanches are responsible for about 75% of fatalities and are most often triggered by the skier or boarder. The most likely time for slab avalanches to occur is during the main winter months of January to March.
They occur when a cohesive layer of snow sits on top of a weaker layer. The cohesive slab on top can often be very large, hence why avalanches of this nature are so dangerous. You get both hard and soft slab avalanches. Hard slabs are where the top layer has been tightly bonded, usually by the wind, but remains sitting on top of a weak layer. These are harder to trigger but often result in large and deadly slides.
Slab avalanches release as a single slab but then break up as the slide happens. Soft slab avalanches can break up into fast powdery avalanches while hard slab slides can often break up into large and destructive blocks.
These are most likely to occur after heavy snowfall. If it has been snowing heavily at more than 2cm per hour this type of avalanche is especially likely. Powder avalanches can travel extremely fast - often in excess of 100mph. Very high powder clouds can occur and a blast wave can precede the actual snow. Such avalanches can be very destructive and snow inhalation and suffocation can be another danger to those in the way.
This type of avalanche commonly occurs in warm spring conditions. They occur when water flows through the snow weakening the bonds. They can be large, and often the entire snow depth can slide, but they travel very slowly at around 5-10mph. This makes them much easier to avoid and also they are usually the easiest type to predict.